/*
 * Portions Copyright  2000-2009 Sun Microsystems, Inc. All Rights
 * Reserved.  Use is subject to license terms.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 only, as published by the Free Software Foundation.
 * 
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License version 2 for more details (a copy is
 * included at /legal/license.txt).
 * 
 * You should have received a copy of the GNU General Public License
 * version 2 along with this work; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 * 
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
 * Clara, CA 95054 or visit www.sun.com if you need additional
 * information or have any questions.
 */

package javax.xml.stream;

/**
 * This interface is used to resolve resources during an XML parse.  If an application wishes to 
 * perform custom entity resolution it must register an instance of this interface with
 * the XMLInputFactory using the setXMLResolver method.  
 *
 * @version 1.0
 * @author Copyright (c) 2003 by BEA Systems. All Rights Reserved.
 */
public interface XMLResolver {

  /**
   * Retrieves a resource.  This resource can be of the following two return types:
   * (1) java.io.InputStream (2) javax.xml.stream.XMLStreamReader 
   * If this method returns null the processor will attempt to resolve the entity using its
   * default mechanism.
   *  
   * @param publicID The public identifier of the external entity being referenced, or null if none was supplied.
   * @param systemID The system identifier of the external entity being referenced.
   * @param baseURI  Absolute base URI associated with systemId.
   * @param namespace The namespace of the entity to resolve. 
   * @return The resource requested or null.
   * @throws XMLStreamException if there was a failure attempting to resolve the resource.
   */
  public Object resolveEntity(
      String publicID, String systemID, String baseURI, String namespace)
    throws XMLStreamException;
}
